Portability and ease of use are important for many new electronic products offering communications capabilities, data processing facilities and data entry and storage arrangements. Providing these and other features in a user-friendly and convenient package requires additional sophistication in circuit design and places a premium on performance as compared to weight of the product.
Conventional printed circuit cards provide a rugged and robust vehicle for realizing electronic circuitry of almost arbitrary complexity and sophistication. However, printed circuit cards invest substantial mass in the card itself, typically a fiberglass and epoxy matrix. It has been especially uneconomical and impractical to provide lightweight printed wiring boards wherein the ratio of the mass of the active circuitry to the mass of the product approached unity.
This problem is exacerbated in products having functional requirements sufficiently different as to preclude forming the product from a single monolithic circuit. For example, a handheld telephone requires digital circuitry for accomplishing dialing, memory functions such as speed dialing and cryptographic or other techniques for foiling unauthorized use. Also required are radio frequency circuits, operating in the neighborhood of a GigaHertz, which are not amenable to monolithic cointegration with power-efficient digital circuits using present-day integrated circuit fabrication capabilities. In such products, it is extremely desirable to reduce the weight of elements incorporated to interconnect distinct functional blocks having immiscible design requirements.
What is needed is a method for reducing the mass of the interconnections required between circuitries having functional differences presently precluding their cointegration in monolithic form.